Manufacture of purifying materials



IUNITEIDSTVATES. PATENT OFFICE.

CORNELIUS MASSATSCH, or BEBLIN-TEMPELHOF, GERMANY, ASSIGNOR 'ro rim rnamurrroomrrmr, or new YonK, N. Y., A CORPORATION or DELAWARE.

MANUFACTURE Oh PURIFYING MATERIALS.

No Drawing.

' To all whom it may concern:

Be it known that I, CORNELIUS MAssArsorr, a subject of the German Emperor, residing at Berlin-Tempelhof, Germany, have 1nvented certain new and useful Improvements in the Manufacture of Purifying Materials, of which the following is aspecification;

This invention relates to the manufacture of purifying materials; and it comprises a or potassium silicate),

*contained. alkali, is then cautiously at a temperature below method of preparing a base-[exchangin purifying material in the wet way as har mechanically strong and resistant'granules of pervious nature suitable for the purification of water and other pm a precipitatedor wet masso taining silica,

material con tating a solution of an aluminate of an alkali 'metal (such as potassium .aluminate or sodium aluminate) by a solution of a silicate of an alkali metal (such as sodium'silicate this material is washed to remove a part, but not all, of the indurated by drying 100 C. until a art, but not all, of the con? tained water 0 hydration is removed and the mass acquires a stony or horny appearance and the property of breaking up with water and the dried material is once more treated with water or rehydrated to cause it oses, whereinalumina and. alkali is pre pared in any suitable manner, as by prec1p1- to break up and granulate}. and it further comprises as a new article of manufacture a base-exchanging and water purifying mat'erial in hard, pervious granules exhibiting no tendency to slime with water,

. ules having the composition of-an indurated,

.and many ways have been propose chemical and physical, must be met by a technically satisfactory material; a material which when used in granular form in urinature of a" ltkrand of long life,-

fyin'g beds of the general ing bed will be durable such granwater by exchange of its Specification of Letters Patent. Patented June 22, 1920.

Application filed August 18, 1914. Serial No. 857,373.

tion without sliming or crumbling. It must of course have a high exchange power so that a given weight may take up, for instance, as great a per cent. of lime and magnesia as possible in softening hard water beexchange power necessitates material of porous or pervious nature in order to secure a maximum active area for contact with the water or other liquid to be purified and the granules must be small and reasonably uniform in size. On the other hand the material must be mechanically strong; it must have sufficient strength when used in beds or columns to support not only the weight of the material itself inthe bed but the weight and pressure of the water or other liquid to be treated. And the ranules must retain theirshape for an in efinite time without mashing down or mudding together and they must not slime, erodeiior wash away.

Naturally, material-r combining high chemical activity and porosity with extreme physical. resistivity andgreat mechanical strength is not readily prepared;and particularly in the wet way.- High exchange power, that is high chemical reactivity, may be exhibited by many precipitates which can be formed in the wet way, as by precipitating a solution of potassium aluminate'by one of sodium silicate; but I such precipitates are in a physical state rendering them useless for practical utilization, being usually gelatinous or gummy. The physical character of the precipitate varies according to the circumstances, such as the' concentra tion of the reacting liquids, the temperature,

withstanding repeated use and revivificafore revivification becomes necessary. High etc. Fre uently it forms as a translucent I jelly, at rst filling the entire liquid and then gradually becoming lumpy. Sometimes this lumplng takes place only on heating, sometimes the precipitate forms as flakes which then easily coalesce or adhere together as lumps. These precipitates are substantially useless for filtration purposes and cannot be used technically. Simple drying and he ating do not suifice to convert these precipitates into material useful for technical purposes, drying, unless done in a special way, as hereinafter indicated, being a t to give a product sliming with water.

eating to high temperaturesand complete dehydration causes loss of reactivity. For

.these reasons in the existing commercial art the exchange material is not made in the wet way but is prepared by a fusion process; a glass being prepared and this being afterward granulated, extracted and hydrated in special ways.

I have found, however, that a material exhibiting the necessary combination of chemical, physical and mechanical 'properties may be simply, easily and economically prepared by a particular treatment of the slimy, gelatinous or gummy alumino-silicate precipitates or materials made in the various wet methods. Any of the known wet methods may be employed for making this precipitate or initial material but that formed by precipitating a solution of an aluminate of an alkali metal by a silicate of an alkali metal is particularly suitable. The alkaline base of the silicate and 0f the aluminate may be either soda or potash. Both may be present in the reacting solution.

One suitable precipitate may be made by mixing equivalent amounts of solutions of potassium aluminate and sodium silicate. A solution of aluminate containing both soda and potash as bases is still better. The silicate solution may be in excess without harm. A solution of ordinary water glass (sodium silicate) may be used, it being-immaterial whether the dissolved silica is present as chemically pure sodium silicate or as polysilicates. In the precipitation a portion of the alkali separates and remains in solution, while a portion remains in the precipitate. The solutions may or may not con tain foreign salts as sodium chlorid, sodium sulfate, etc, and may be dilute or concentrated. Dilute solutions may give a precipitate which is. in a degree, flaky and easier to wash and handle in the hereinafter described process, but concentrated, or even saturated, solutions are more economical. Precipitation may be effected atthe ordinary temperature or may be effected with hot solutions. A precipitate made by mixing a solution of aluminum sulfate with a solution of potash or soda silicate under conditions giving an alkaline admixture, is also suitable. Suitable material may also be made by treating sodium aluminate solu- Lion; with hydrated silica. Additions of hydrated silica before precipitation are also sometimes useful in the previously described methods. F or example, a solution of an aluminate of an alkali metal may be treated with precipitated silica. The materials made in any'of these ways contain coprecipitated alkali. They may be treated with calcium chlorid to replace contained soda or potash by lime prior to the hereinafter described process. Or a solution of calcium chlorid may be added during precipitation.

\Vet, voluminous, ummy, gelatinous or flaky materials precipitated or otherwise rial obtained in a certain stage of the operatlon; water causing the hard material to decrepitate or break up into small angular granules of the desired character and size. This decrepitation or breaking up appears to be, at least in part, due to a retention of a proportion of alkali in the dried material; a condition which. will result from the retention therein of a certain proportion of the mother liquor.

In the process hereinafter specifically described this result of leaving a proportion of the mother liquor in the dried precipitate is insured by regulatin the washing operation to which the precipitated material is subjected; this operation being so controlled that while much of the alkali (or mother liquor containing alkali), is removed a proportion thereof still remains in the washed precipitate. Upon the degree of washing depends much of the character of the final material. There are a. number of incidental advantages to this partial washing; one being that it greatly shortens the time of operation and lessens the amount of water required, thereby materially reducing the cost of operation. Before, during or after this washing the materialis advantageously but not necessarily submitted to pressure to compact it. Both the partial washing and the compression may be effected in a filter press; thereby enabling washing and compression to be rapidly effected as the time required for passing each lot of precipitate through the press is comparatively short. Further, the filter press'cake so made is in better condition for subsequent operations than if all the alkali in solution had been entirely removed. After washing and compression the material is next slowly and carefully indurated b drying it at a temperature below 100 A temperature of about 753 C. is advan tagcous. The time during which the drying operation is continued of course depends on the particular apparatus used and upon the formed with the quantity of liquid reduced,

thereby reducing, to that extent, the necessity for washing in removing the desired amount of alkali,- but the material is in better condition for induration and rehydratlucent, hard granules.

ing as hereinafter described. During induration the material hardens gradually to form a translucent hornlike mass having 'a white to grayish-yellow color (according to the purity of the materials) and a shelllike or conchoidal fracture. When properly indurated the material, becomes a white stony mass which upon treatment with hot or cold water breaks up with strong decrepitation into small angular, more or less transduration treatment may be known by the occurrence of this action on treating a sample with water. Thisbreaking up is probably in part due to solution of retained alkali and in part to a rehydration of'tlie indurated mass. At this time the drying or induration is interrupted and the material once more treated with water. Part of this retained alkali is removed by this'treatment. On treatment with water either cold or hot the indurated material breaks up into granules having a diameter of 1 to 3 millimeters. "These granules which represent a" highly active artificial zeolite, are washed and are then ready for use. This second washing or lixiviation may be performed in special vessels or apparatus or may be done in the final apparatus or filters inwhich the materialis ultimately to be used.

material obtained by direct precipitation of 'aluminate solution by silicate solution beused, if the washing is carried so far that a liter of the final wash water requires at least 0.5 cc. but not more than 15 cc. of normal hydrochloric acid (a solution containout their mass, showing a minute perviousness and, therefore, admit of a great surface action. dyes, such as a solution of methylene blue, the granules become colored throughout their mass. They are highly active'in exchange, taking up relatively great amounts of lime or other base before requiring revivification. But in spite of their porosity the granules are strong, easily supporting the weight of a filter .bed or column withoutmashing down, eroding, or sliming, even after long continued use. The sharp angles remain after long use and a filter bed or column retains its perviousness. They are composed substantially of alumina, silica,

The end of the in-' On treatment with suitable driven off and the loss is partially replaced in the subsequent water treatment.

While I have hereinbefore described the present process as applied to exchange matrials containing alumina, silica and alkali,

Y or alkali and lime, it mayalso be advantageously used with exchange materials prepared in thewet way and containin other alkali-soluble,.or amphoteric oxids that is "oxids which, like alumina, have both acid and basic properties) such as lead oxid, tin

oxid, zine oxid, titanic oxid, etc., replacing a part or all of the alumina. Materials containing other bases than lime, such as drying, in the event that it is to be stored strontia, baryta,'magnesia, manganese oxid, etc., may also be sotreated.

After the second washing, the material may be again cautiously dried, as by air or shipped. .Otherwise it may be simply. dumped wet into the purifiers in which it is to be used if the final (second) washing has not been effected in such purifiers, as

' it may be. In drying, it is desirable not In the first washing stage, presuming the to remove more than thewater mechani- 'cally present as moisture; the material should not be further dehydrated. If this drying be pushed too far the material may become crumbly or form dust to some extent.

prior to the indurating operation is of great advantage in obtaining the desired mechanically strong, minutely pervious material.

In using filter presses it is best to use pres-.

' The pressure applied to the wet material I sures in excess of those which will sufiice to press out the water. Advantageously,

' the pressure may be very much higher.

course in this respect much depends upon 'the particular physical characteristics of the wet material which is being treated and the dimensions of the cake under pressure.

But as a general rule with ordinary filter. presses at least 6 to Sqpounds pressure per square inch is used. s the wet material enters the press it contains much moisture in what may be called a mechanically intermingledstate. This moisture should be pressed out as completely as possiblesince coprecipitated alumina, silica and alkali till a portion but not all of the alkali is reinoved and indurating by drying at low temperatures.

2. The process of making a granular water-purifying substance whichcomprises washing a hydrated material comprising coprecipitated alumina, silica and alkali till a-portion but not all of the alkali isgremoved, indurating. by drying at low temperatures and treating with water.

3. The process of making a granular water-purifying substance which comprises precipitating a solution of aluminate by a solution of silicate, washing the precipitate, removing a portion but not all of the alkali, indurating by drying at a temperature be low 100 (1. and treatin with water.

4. The process of ma ing a granular Water purifying substance which comprises precipitating a solution of aluminate bya solution of silicate, washing the precipitate until a liter of the washing water requlres for its neutralization at least 0.5 cubiccentimeters of normal hydrochloric acid but not more than 15 cubic centimeters of normal hydrochloric acid, pressing the precipitate, indurating by drying at a temperature below 100 C. until the material decrepitates with water and treating with water.

5. The process of preparing material for treating water which comprises producing in an alkaline medium, a precipitate containing alkali, alumina and silica, washing this precipitate until a substantial proportion of alkali is removed with the wash water while a substantial proportion of alkali still remains in the precipitate, indurating by drying the so treated precipitate until a portion but not all of the water of hydration has been removed and the material decrepitates with water and treating the dried material with water.

6. The process of preparing a hard granular material for purifying water and similar purposes which comprises producing a precipitate containing an alkali, silica and an alkali soluble oxid, washing till a portion but not all of the alkali is removed, in-

durating at a low temperature until a sample of the material ontreatment with water" breaks up into granules and then rewashing.

7. The process of making a granular water purifying substance which comprises washing a hydrated coprecipitated silica, alkali and alkali-soluble oxids till a portion but not all of said alkali is removed, indurating by drying at low temperatures and 9. In; the manufacture of granular waterpurifying materials the process of treating materials comprising coprecipitated silica, alkali and alumina which comprises washingand pressing such a material, the wash ing being carried to a point where a substan+ tial proportion of such alkali is removed while a substantial proportion still remains," indurating the washed and pressed material by drying at low temperatures and washing with water.

10. In the manufacture of granulated walter-purifying materials from wet hydrated precipitates containing silica, alkali and alkali-soluble oxid, the process which comprises washing and compressing such a material, the pressure being higher than that which is necessary merely to remove the excess of mechanically held water and the washing being suilicient to remove asubstantial proportion but not all of the contained alkali, and thereafter indurating the washed and pressed material by drying at a low temperature until a sample on treatment with water will break up into angular granules. I p

11. In the manfacture of granulated water-purifying materials from Wet'hydrated precipitates containing silica, alkali and alumina, the process which comprises washing and compressing such a material, the

pressure being higher than that which isnecessary merely to remove the excess of mechanically .held water and the. washing being suliicient to remove a substantial proportion but not all of the contained alkali, and thereafter indurating the washed and pressed material by drying at a low tem- 12.111 the manufacture of water purify- -ing niaterials the process. which comprises producing a dried hard mass of coprecipitated silica and alumina, said mass also contaming alkaline mother liquor, and treating perature until a sample on treatment with f water will breakup into angular granules.

the same with water to cause it'to break up into small granules or fragments.

14. As a new article of manufacture, a hard granular translucent material coinposed of alumina, silica, alkali, and water ofhydration, the granules exhibiting n0 viS- silica and alumina, said mass containing a ible pores, but on treatment with phenolphthalein solution becoming pink throughout their mass, such granules having the properties of a precipitate from an alkaline solution deprived of part but not all of its free alkali.

15. As a new article of manufacture, a hard granular translucent material composed of silica, alkaliand alkali-soluble oxid, and Water of hydration, the granules exhibiting no visible pores, but on treating pink throughout their mass, such granules having the properties of a precipitate from an alkaline solution deprived of part but not all of its free alkali.

16. A hard dried mass/of coprecipitated proportion of alkaline mother liquor and being capable of breaking up into small granules or fragments on treatment with water.

- In testimony whereof, I afiix my signature in the presence of two subscribing witnesses.-

CORNELIUS MASSATSCH.

Witnesses:

HENRY HASPER, WOLDEMAR HAUPT. 

